Liquid removal system having improved dryness of the user facing surface

ABSTRACT

The present invention provides a liquid removal system for applications where there is a need for liquid removal including laboratories and workshops as well as medical applications and dental applications. The urine acquisition zone of the liquid removal system of the present invention has a skin hydration value of less than 200 milligrams and hence reduces phenomena related to liquid rewet from the liquid removal system.

FIELD OF THE INVENTION

[0001] The present invention provides a liquid removal system forapplications where there is a need for liquid removal includinglaboratories and workshops as well as medical applications as well asdental applications.

BACKGROUND

[0002] Articles to manage body exudates such as urine are well known inthe art. In this context, managing body exudates includes acquiring,distributing, and storing body exudates such as urine, menses fecalmaterial, and the like. A wide variety of article has been proposedincluding diapers, sanitary napkins, adult incontinence articles such asbriefs or bed mats, underarm sweat pants, catheters, bottles, bed pans,and the like.

[0003] In U.S. Pat. No. 5,678,564 (Lawrence et al.) and U.S. Pat. No.5,911,222 (Lawrence et al.) a liquid removal system having an interfacedevice and a vacuum source is described. The interface device has aporous membrane with an entrance zone on one side. The vacuum sourcemaintains a vacuum on the side of the membrane opposite the entrancezone when the membrane is wetted. Liquid which contacts the wettedporous membrane is removed from the interface device by the vacuumsource. Due to its specific construction such as for example by having aexposed wetted membrane on its user facing surface, this liquid removalsystem not only causes a damp or wet feeling it may further lead tooverhydration of the skin and finally to substantial skin problems suchas irritations or infections.

[0004] Accordingly, it is an object of the present invention to providea liquid removal system which overcomes the problems posed by the priorart.

[0005] It is a further object the present invention to provide liquidremoval system which comprises a user facing surface with improveddryness during use.

SUMMARY OF THE INVENTION

[0006] The present invention provides a liquid removal system whichcomprises an interface device, said interface device comprising

[0007] a first zone and

[0008] a second zone and having

[0009] a porous membrane separating said first zone from said secondzone,

[0010] said second zone being adapted to be connected to a suctionsource, said porous membrane being capable of maintaining a suction insaid second zone without permitting air from said first zone to passthrough said membrane into said second zone when said membrane has beenwetted with a first liquid; said suction being maintained until saidmembrane is contacted with a second liquid; and wherein said secondliquid upon entering said first zone and contacting said porous membraneis removed from said first zone by said suction in said second zone bypassing through said membrane into said second zone, said first zonehaving a user facing surface, said the second zone having a backsurface, said user facing surface having a urine acquisition zone. Theliquid removal system of the present invention is characterized in thatthe liquid removal system has a skin hydration value of less than 200milligrams according to the collagen rewet test defined herein.

[0011] The present invention further provides a liquid removal systemwhich comprises an interface device, said interface device comprising

[0012] a first zone and

[0013] a second zone and having

[0014] a porous membrane separating said first zone from said secondzone,

[0015] said second zone being adapted to be connected to a suctionsource, said porous membrane being capable of maintaining a suction insaid second zone without permitting air from said first zone to passthrough said membrane into said second zone when said membrane has beenwetted with a first liquid; said suction being maintained until saidmembrane is contacted with a second liquid; and wherein said secondliquid upon entering said first zone and contacting said porous membraneis removed from said first zone by said suction in said second zone bypassing through said membrane into said second zone, said first zonehaving a user facing surface, said the second zone having a backsurface, said user facing surface having a urine acquisition zone. Theliquid removal system of the present invention is characterized in thatsaid urine acquisition zone is completely covered by a hydrophobicapertured topsheet.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Materials suitable for the membrane of the present invention andsuction sources suitable for the liquid removal system of the presentinvention are described for example in U.S. Pat. No. 5,678,564 (Lawrenceet al.) U.S. Pat. No. 5,911,222 (Lawrence et al.) incorporated herein byreference. Preferably, the membrane material can be bend to an extendwhich includes most of the typical in-use conditions withoutsubstantially loosing its functionality. More preferably, the membranematerial of the present invention has a low bending moment in thelongitudinal and/or the transverse direction in order to improve thecomfort of the system. Preferably, the suction source as a whole or atleast those parts connecting the suction source with the second zone ofthe liquid removal system are chosen to be flexible and/or compressiblein order to improve the comfort of the system.

[0017] For the purpose of the present invention, a locally Cartesiancoordinate system is defined relative to the liquid removal system andits positioning relative to the wearer during use. The longitudinal orx-direction is defined as the direction running from the front waistregion of the wearer to the back waist region of the web. Typically, thelongitudinal direction is the longest dimension of the liquid removalsystem. The transverse or y-direction is defined as direction runningfrom the left side of the wearer to the right side of the wearer. Thez-direction is normal to the x-direction and to the y-direction andaccordingly is also substantially normal to the body surface of thewearer during use. It is to be understood in this context that duringwear of the liquid removal system of the present invention the liquidremoval system conforms to the body shape of the wearer and thataccordingly the coordinate axis at the front region of the liquidremoval system may not coincide with the coordinate axis in the backregion of the liquid removal system.

[0018] The liquid removal system of the present invention has a userfacing surface with a low rewet in order to minimize the impact of therewet onto the skin of the wearer.

[0019] The urine acquisition zone of the liquid removal system of thepresent invention is completely covered by a hydrophobic aperturednonwoven topsheet. Hydrophobic apertured nonwoven web materials yield tobenefits, on one hand they allow for quick penetration of acquired bodyliquid through the thickness dimension because of the apertures, on theother hand they do not retain liquid in their pores due to thehydrophobic nature of the fiber surface.

Topsheet

[0020] The topsheet of the present invention has a first or innersurface oriented toward the interior of the interface device of theliquid removal system, and an opposed second or outer surface orientedtoward the skin of the wearer when the liquid removal system is used.

[0021] The topsheet is compliant, soft feeling, and non-irritating tothe wearer's skin. Further, the topsheet is liquid pervious, permittingliquids (e.g., urine) to readily penetrate through its thickness. Asuitable topsheet may be manufactured from a wide range of materials,such as porous foams; reticulated foams; apertured plastic films; orwoven or nonwoven webs of natural fibbers (e.g., wood or cottonfibbers), synthetic fibbers (e.g., polyester or polypropylene fibbers),or a combination of natural and synthetic fibbers. Preferably, thetopsheet is made of a hydrophobic material to isolate the wearer's skinfrom liquids contained in the liquid storage structure.

General Properties

[0022] Functional Properties

[0023] The topsheet of the present invention is preferably hydrophobicand in order to minimize liquid retention in the topsheet and tominimize liquid rewet from the liquid handling structure or the liquidstorage structure back to the skin of the wearer.

[0024] Optionally, the topsheet of the present invention may also beoleophobic in order to minimize liquid retention in the topsheet and tominimize liquid rewet from the liquid handling structure or the liquidstorage structure back to the skin of the wearer.

[0025] The topsheet of the present invention may have a liquid retentionin the topsheet according to the Liquid-Retention Test definedhereinafter of less than 50 mg, preferably less than 40 mg, morepreferably less than 30 mg, most preferably less than 20 mg for a testliquid having a surface tension of about 62 mN/m.

[0026] The topsheet of the present invention may have a liquid retentionin the topsheet according to the Liquid-Retention Test definedhereinafter of less than 150 mg, preferably less than 120 mg, morepreferably less than 90 mg, most preferably less than 70 mg for a testliquid having a surface tension of about 33 mN/m.

[0027] The contact angle of the user facing side of the topsheet of thepresent invention with distilled water having a surface tension of atleast 72 mN/m may be at least 90°, preferably at least 100°, morepreferably at least 110°, even more preferably at least 120°, mostpreferably more than 125°. High contact angles reduce the capillarysuction of the pores of the topsheet. Contact angles of more than 90°even result in a negative the capillary suction, hence rendering therespective pores water repellent.

[0028] Structural Properties

[0029] The topsheet preferably has a plurality of apertures with aneffective aperture size of at least 0.2 square millimeters, morepreferably, the plurality of apertures have an effective aperture sizeof at least 0.5 square millimeters, even more preferably, the pluralityof apertures have an effective aperture size of at least 1.0 squaremillimeters, and most preferably, the plurality of apertures have aneffective aperture size of at least 2.0 square millimeters. Effectiveapertures are those which have a gray level of 18 or less on a standardgray level scale of 0-255, under the image acquisition parametersdescribed below.

[0030] The topsheet preferably can have an effective open area of atleast 15 percent, more preferably the topsheet has an effective openarea of at least 20 percent, even more preferably, the topsheet has aneffective open area of at least 25 percent, and most preferably thetopsheet has an effective open area of at least 30 percent.

[0031] A method to determine effective aperture size and open area isdescribed in the method section.

[0032] Manufacturing Techniques

[0033] Suitable materials and structures for use as the topsheet mayinclude apertured nonwoven webs, apertured films, apertured formedfilms, scrims, woven webs, scrim, netting, macroporous thin foams,composites of the aforementioned materials, and the like. There are anumber of manufacturing techniques which may be used to manufacture thetopsheet 24. For example, the topsheet may be a nonwoven web of fibbersspunbonded, carded, wet-laid, meltblown, hydroentangled, combinations orcomposite laminates of the above, or the like. Preferred topsheetsinclude a carded/carded composite, hydroentangled over a wire formingscreen and thermally air-through bonded by means well known to thoseskilled in the nonwovens art and hydroentanglement of fibrous webs.

[0034] Surface Treatment

[0035] The topsheet of the absorbent article of the present inventionmay comprises a surface finish to increase the surface energy of thetopsheet to at least 40 mN/m, preferably at least 45 mN/m, morepreferably 50 mN/m, most preferably at least 60 mN/m. Suitablesurfactants and suitable manufacturing techniques are well known in theart.

[0036] The topsheet of the present invention may also comprise a surfacefinish reducing the surface free energy of at least a part of thesurface of the topsheet and hence rendering this part of the surfaceeven more hydrophobic and eventually oleophobic.

[0037] The structured may comprise hydrophobicity gradients in adirection parallel to the major surfaces of the topsheet to provideindividual liquid handling properties in different regions of thetopsheet. The topsheet may also comprise a hydrophobicity gradient in adirection perpendicular to the major surfaces of the topsheet in orderto enhance liquid transfer through the topsheet.

[0038] At least a part of the surface, and in particular of the surfacefacing the wearer during use, of the topsheet may comprise a surfacecoating such as a thin fluorocarbon polymer film. Suitable techniques toobtain such a surface coating are well known in the art and aredescribed for example in European patent application No. 98116895.8, inWO 97/42356 (Gleason) and in WO96/00548 (Ouellette). Another suitablesurface treatment is a silicone release coating from Dow Corning ofMidland, Mich. available as Syl-Off 7677 to which a cross-linkeravailable as Syl-Off 7048 is added in proportions by weight of 100 partsto 10 parts, respectively. Another suitable surface treatment is acoating of a UV curable silicone comprising a blend of two siliconescommercially available from General Electric Company, Silicone ProductsDivision, of Waterford, N.Y., under the designations UV 9300 and UV9380C-DI, in proportions by weight of 100 parts to 2.5 parts,respectively. Another suitable treatments include fiber finishsavailable from Fibervisions of Varde, Denmark, under the designationsT190 and T198, a fiber finish available from Schill and Seilacher ofBöblingen, Germany, under the designation Silastol FC1760, a melt-inadditive available from the Minnesota Mining And Manufacturing Company,of St. Paul, Minn., USA. Other suitable treatment materials include, butare not limited to, fluorinated materials such as fluoropolymers (e.g.,polytetrafluoroethylene (PTFE), commercially available under the tradename TEFLON) and chlorofluoropolymers. Other materials which may provesuitable for providing regions of reduced surface energy includePetrolatum, latexes, paraffins, and the like.

[0039] The topsheet of the present invention may comprise hydrophobicand oleophobic polymers. Processes to manufacture such polymers andarticles therefrom is well known in the art and are described forexample in U.S. Pat. No. 3,870,767 (Grimaud).

[0040] Optionally, the topsheet of the present invention may be treatedby modulated plasma glow discharge treatments as described in Europeanpatent application No. 98116895.8 (D'Agostino et al., P&G case CM1893FQ) and European patent application No. 98116894.1 (D'Agostino, P&Gcase CM 1894FQ).

[0041] Skin Care Composition

[0042] The outer surface of the topsheet may comprise an effectiveamount of a skin care composition which is semi-solid or solid at 20° C.and which is partially transferable to the wearer's skin. In preferredembodiment of the absorbent article of the present invention, theabsorbent article additionally comprises an skin care composition whichis at least partially transferable to the skin of the user during theintended use. Preferably, such an oil-containing composition ispositioned on a user facing surface of the absorbent article. Theoil-containing composition may also be deployed in such a way that it isonly released at the time of intended use such as beingmicroencapsulated.

[0043] Skin care compositions suitable for the absorbent article of thepresent invention are described for example in WO96/16682 (Roe et al.).

[0044] Preferably, the skin care compositions suitable for the absorbentarticle of the present invention have a melting profile such that theyare relatively immobile and localized regarding their positioning withinthe absorbent article at room temperature, are transferable to the userat body temperature, and yet are not completely liquid under extremestorage conditions. Importantly, the skin care compositions of thepresent invention are easily transferable to the skin by way of normalcontact, user motion, and/or body heat.

[0045] The skin care compositions suitable for the absorbent article ofthe present invention are solid, or more often semisolid, at 20° C.,i.e. at ambient temperatures. By “semisolid” it is meant that the skincare composition has a rheology typical of pseudoplastic or plasticfluids. When no shear is applied, the skin care compositions can havethe appearance of a semi-solid but can be made to flow as the shear rateis increased. This is due to the fact that, while the skin carecomposition contains primarily solid components, it also includes someminor liquid components.

[0046] The skin care compositions suitable for the absorbent article ofthe present invention are at least semi-solid at room temperature tominimize skin care composition migration. In addition, the skin carecompositions preferably have a final melting point (100% liquid) abovepotential “stressful” storage conditions that can be greater than 45° C.

[0047] Specifically, the skin care compositions suitable for theabsorbent article of the present invention should have the followingmelt profile: Characteristic Preferred Range Most Preferred % liquid atroom temp (20° C.)  2-50  3-25 % liquid at body temp. (37° C.) 25-9530-90 final melting point (° C.) > = 38 > = 45

[0048] By being solid or semisolid at ambient temperatures, these skincare compositions do not have a tendency to flow and migrate into theinterior of the absorbent article to which they are applied. This meansless skin care composition is required for imparting desirabletherapeutic or protective coating benefits.

[0049] When applied to the user facing surface of absorbent article ofthe present invention, the skin care compositions suitable for theabsorbent article of the present invention are transferable to theuser's skin by normal contact, user motion, and/or body heat.

[0050] A preferred embodiment of the absorbent article of the presentinvention contains an effective amount of an skin care composition. Asused herein, the term “effective amount of an skin care compositioncoating” refers to an amount of a particular skin care compositionwhich, when applied to a diaper topsheet, will be effective infulfilling their protective, therapeutic, or cosmetic intention. Ofcourse, the effective amount of a skin care composition coating willdepend, to a large extent, on the particular skin care composition used.

[0051] The skin care compositions suitable for the absorbent article ofthe present invention comprise: (1) an emollient(s); (2) an immobilizingagent(s) for the emollient; (3) optionally a hydrophilic surfactant(s);and (4) other optional components.

[0052] The viscosity of the formulated skin care compositions, includingemollient, immobilizing agent, and optional components should be as highas possible to keep the skin care composition from flowing into theinterior of the absorbent article. Unfortunately, high viscosities canalso lead to skin care compositions that are difficult to apply withoutprocessing problems. Therefore, a balance must be achieved so theviscosities are high enough to keep the skin care compositions localizedon the user facing surface of the absorbent article, but not so high asto cause processing problems. Suitable viscosities for the skin carecompositions will typically range from about 5 to about 200 centipoises,preferably from about 15 to about 100 centipoises, measured at 60° C.

[0053] Emollient

[0054] The key active ingredient in these skin care compositions is oneor more emollients. As used herein, an emollient is a material thatsoftens, soothes, supples, coats, lubricates, moisturizes, or cleansesthe skin. An emollient typically accomplishes several of theseobjectives such as soothing, moisturizing, and lubricating the skin. Forbeing suitable to be used in the absorbent article of the presentinvention, these emollients have either a plastic or fluid consistencyat i.e., at ambient temperatures. This particular emollient consistencyallows the skin care composition to impart a soft, lubricious,lotion-like feel.

[0055] Emollients useful in the absorbent article of the presentinvention can be petroleum-based, fatty acid ester type, alkylethoxylate type, fatty acid ester ethoxylates, fatty alcohol type,polysiloxane type, or mixtures of these emollients. Suitablepetroleum-based emollients include those hydrocarbons, or mixtures ofhydrocarbons, having chain lengths of from 16 to 32 carbon atoms.Petroleum based hydrocarbons having these chain lengths include mineraloil (also known as “liquid petrolatum”) and petrolatum (also known as“mineral wax,” “petroleum jelly” and “mineral jelly”). Mineral oilusually refers to less viscous mixtures of hydrocarbons having from 16to 20 carbon atoms. Petrolatum usually refers to more viscous mixturesof hydrocarbons having from 16 to 32 carbon atoms. Petrolatum andmineral oil are particularly preferred emollients for skin carecompositions of the present invention.

[0056] Immobilizing Agent(s) for the Emollient

[0057] The immobilizing agent counteracts the tendency of the emollientto migrate or flow into the absorbent article of the present inventionby keeping the emollient primarily localized on the surface of theabsorbent article to which the skin care composition is applied.

[0058] Suitable immobilizing agents for the use in the absorbent articleof the present invention can comprise a member selected from the groupconsisting of C₁₄-C₂₂ fatty alcohols, C₁₂-C₂₂ fatty acids, and C₁₂-C₂₂fatty alcohol ethoxylates having an average degree of ethoxylationranging from 2 to about 30, and mixtures thereof. Preferred immobilizingagents include C₁₆-C₁₈ fatty alcohols, most preferably selected from thegroup consisting of cetyl alcohol, stearyl alcohol, and mixturesthereof. Mixtures of cetyl alcohol and stearyl alcohol are particularlypreferred. Other preferred immobilizing agents include C₁₆-C₁₈ fattyacids, most preferably selected from the group consisting of palmiticacid, stearic acid, and mixtures thereof. Mixtures of palmitic acid andstearic acid are particularly preferred. Still other preferredimmobilizing agents include C₁₆-C₁₈ fatty alcohol ethoxylates having anaverage degree of ethoxylation ranging from about 5 to about 20.Preferably, the fatty alcohols, fatty acids and fatty alcohols arelinear.

[0059] Optional Hydrophilic Surfactant(s)

[0060] It is important that the skin care composition also besufficiently wettable to ensure that liquids can rapidly penetrate intoat least the first component of the absorbent article. This diminishesthe likelihood that body exudates will flow off the skin carecomposition coating rather than being drawn into at least the firstcomponent. Depending upon the particular immobilizing agent used in theskin care composition of the present invention, an additionalhydrophilic surfactant (or a mixture of hydrophilic surfactants) may, ormay not, be required to improve wettability.

Other Optional Components

[0061] Oil-based compositions can comprise other optional componentstypically present in emollient, creams, and skin care compositions ofthis type. These optional components include water, viscosity modifiers,perfumes, disinfectant antibacterial actives, pharmaceutical actives,film formers, deodorants, opacifiers, astringents, solvents and thelike. In addition, stabilizers can be added to enhance the shelf life ofthe skin care composition such as cellulose derivatives, proteins andlecithin. All of these materials are well known in the art as additivesfor such formulations and can be employed in appropriate amounts in theskin care compositions of the present invention.

[0062] As is readily apparent to the skilled person, the reduction ofsurface wetness can only be achieved by providing a liquid removalsystem exhibiting a sufficient performance for example in terms ofacquisition rate, liquid transportation rate, storage capacity, membraneperformance, and the like.

[0063] In the following, a suitable embodiment of the liquid removalsystem and of suitable members for a liquid removal system respectivelywill be described. The liquid removal system is assembled from an opencelled foam material which is completely enveloped by a membrane. Asuitable membrane material is available from SEFAR of Rüschlikon,Switzerland, under the designation SEFAR 03-20/14. A suitable foammaterial is available from Recticel of Brussels, Belgium, under thedesignation Bulpren S 10 black. A suitable technique to completelyenvelope the foam material with the membrane material is to wrap themembrane material around the foam material and to subsequently heat sealall open edges of the membrane material. It will be readily apparent tothe skilled practitioner to choose other similarly suitable materials.Depending on the specific intended application of the liquid removalsystem, it may also be required to choose similar materials withslightly different properties. After assembly, the liquid removal systemis activated by immersing the liquid removal system in water or insynthetic urine until the liquid removal system is completely filledwith liquid and until the membranes are completely wetted with liquid.After activation, a part of the liquid inside the liquid removal systemmay be squeezed out by applying an external pressure to the liquidremoval system. If the activation of the liquid removal system wassuccessful, the liquid removal system should not suck air through themembranes.

[0064] The particular geometry of the liquid removal system of thepresent invention can be varied to according to the specificrequirements off the intended application. If, for example, the liquidremoval system is intended to be used in an absorbent article the liquidremoval system may be defined such that its zone of intended liquidacquisition fits between the legs of the wearer and further that itsintended liquid discharge zone matches the form of the storage memberassociated to it. Accordingly, the outer dimensions of the liquidremoval system such as length, width, or thickness may also be adaptedto the specific needs of the intended application. In this context, ithas to be understood, however, that the design of the outer form of theliquid removal system may have an impact on its performance. Forexample, the cross section of the liquid removal system directly impactson its flow rate.

[0065] For application of the liquid removal system in an absorbentarticle according to the present invention, the liquid removal system iscombined with a storage member. The term “liquid storage member” refersto an article which is capable of acquiring and storing liquid. Thevolume of the liquid storage member may vary with the amount of storedliquid such as by swelling. Typically, the storage member will imbibethe liquid by means of capillary suction and/or osmotic pressure. Otherstorage members may also use vacuum as a means to store the liquid. Theliquid storage member is further capable of holding at least a portionof the stored liquid under pressure. Suitable storage members are wellknown in the art and may comprise for example a super absorbentpolymeric material such as polyacrylate. The storage member may furthercomprise a fibrous structure, such as a pad of cellulosic fibers, inwhich the particulate superabsorbent material is dispersed. In order topick up the liquid discharged from the liquid removal system, thestorage member may be placed in direct liquid communication with theintended liquid discharge zone of the liquid removal system. A suitablestorage member is for example a superabsorbent polymer such as availablefrom CHEMDAL, United Kingdom, under the designation ASAP400.

[0066] Further examples of suitable superabsorbent polymers, often alsoreferred to as “hydrogel forming polymer” or “absorbent gellingmaterial”, are described in U.S. Pat. No. 5,562,646 (Goldman et al.),issued Oct. 8, 1996 and U.S. Pat. No. 5,599,335 (Goldman et al.), issuedFeb. 4, 1997.

[0067] Other liquid removal systems suitable for the purposes of thepresent invention are described for example in the PCT patentapplication No. PCT/US98/13497 entitled “Liquid transport member forhigh flux rates between two port regions” filed in the name ofEhrnsperger et al. filed on Jun. 29, 1998, and in the following PCTpatent applications PCT/US99/14796 entitled “High flux liquid transportmembers comprising two different permeability regions” (P&G caseCM1840MQ) filed in the name of Ehrnsperger et al., PCT/US99/14654entitled “Liquid transport member for high flux rates between two portregions” (P&G case CM 1841 MQ) filed in the name of Ehrnsperger et al.,PCT/US99/14638 entitled “Liquid transport member for high flux ratesagainst gravity” (P&G case CM1842MQ) filed in the name of Ehrnsperger etal., PCT/US99/14633 entitled “Liquid transport member having highpermeability bulk regions and high bubble point pressure port regions”(P&G case CM 1843MQ) filed in the name of Ehrnsperger et al. All ofthese documents are enclosed herein by reference.

[0068] In one embodiment of the present invention, the liquid removalsystem of the present invention is geometrically saturated orsubstantially geometrically saturated with free liquid. The term “freeliquid” as used herein refers to liquid which is not bound to a specificsurface or other entity. Free liquid can be distinguished from boundliquid by measuring the proton spin relaxation time T₂ of the liquidmolecules a according to NMR (nuclear magnetic resonance) spectroscopymethods well known in the art.

[0069] The term “geometrically saturated” as used herein refers to aregion of a porous material in which the liquid accessible void spaceshave been filled with a liquid. The void spaces referred to in thisdefinition are those which are present in the current geometricconfiguration of the porous material. In other words, a geometricallysaturated device may still be able to accept additional liquid by andonly by changing its geometric configuration for example by swelling,although all voids of the device are filled with liquid in the currentgeometric configuration. A device for handling liquids is calledgeometrically saturated, if all porous materials that are part of thedevice and intended for liquid handling are geometrically saturated.

[0070] The term “porous material” as used herein refers to materialsthat comprise at least two phases a solid material and a gas or voidphase—and optionally a third liquid phase that may be partially orcompletely filling said void spaces. The porosity of a material isdefined as the ratio between the void volume and the total volume of thematerial, measured when the material is not filled with liquid.Non-limiting examples for porous materials are foams such aspolyurethane, HIPE (see for example PCT patent application WO94/13704),superabsorbent foams and the like, fiber assemblies such as meltblown,spunbond, carded, cellulose webs, fiber beds and the like, porousparticles such as clay, zeolites, and the like, geometrically structuredmaterials such as tubes, balloons, channel structures etc. Porousmaterials might absorb liquids even if they are not hydrophilic. Theporosity of the materials is therefore not linked to their affinity forthe liquid that might be absorbed. The term “substantially geometricallysaturated” as used herein refers to a member in which at least 90% ofthe macroscopic void volume of the member are geometrically saturated,preferably at least 95% of the macroscopic void volume of the device aregeometrically saturated, more preferably 97% of the macroscopic voidvolume of the device are geometrically saturated, most preferably 99% ofthe macroscopic void volume of the device are geometrically saturated.

[0071] In one embodiment of the present invention, the absorbent articleis a disposable absorbent article such as a diaper, a training pant, asanitary napkin, an adult incontinence article, or the like. Such anabsorbent article may further comprise a liquid pervious topsheet, aliquid impervious backsheet at least partially peripherally joined tothe topsheet. The absorbent article may further comprise an absorbentcore which may serve as a storage member for the urine. Topsheets,backsheet, and absorbent cores suitable for the present invention arewell known in the art. In addition, there are numerous additionalfeatures known in the art which can be used in combination with theabsorbent article of the present invention such as for example closuremechanisms to attach the absorbent article around the lower torso of thewearer.

[0072] Methods

[0073] Unless stated otherwise, all tests are carried out at about 22°C.+/−2° C. and at 35+/−15% relative humidity.

[0074] Unless stated otherwise, the synthetic urine used in the testmethods is commonly known as Jayco SynUrine and is available from JaycoPharmaceuticals Company of Camp Hill, Pa. The formula for the syntheticurine is: 2.0 g/: of KCl; 2.0 g/l of Na2SO4; 0.85 g/l of(NH4)H2PO4; 0.15g/l (NH4)2HPO4; 0.19 g/l of CaCl2; ad 0.23 g/l of MgCl2. All of thechemicals are of reagent grade. The pH of the synthetic Urine is in therange of 6.0 to 6.4.

[0075] Finished-Product-Acquisition Test

[0076] An liquid removal structure is loaded with a 75 ml gush ofsynthetic urine at a rate of 15 ml/s using a pump (Model 7520-00,supplied by Cole Parmer Instruments., Chicago, USA), from a height of 5cm above the sample surface. The time to absorb the urine is recorded bya timer. The gush is repeated every 5 minutes at precisely 5 minute gushintervals until the article is sufficiently loaded. Current test dataare generated by loading four times.

[0077] The test sample, which at least includes the interface device ofthe liquid removal system, is arranged to lie flat on a foam platformwithin a perspex box. In this context, the term “flat” refers to theurine acquisition zone of the liquid removal system. A perspex platehaving a 5 cm diameter opening substantially in its middle is placed ontop of the urin acquisition zone of the sample. Synthetic urine isintroduced to the sample through a cylinder fitted, and glued into theopening. Electrodes are located on the lowest surface of the plate, incontact with the surface of the absorbent structure. The electrodes areconnected to the timer. Loads are placed on top of the plate tosimulate, for example a baby's weight. A pressure of 50g cm-2 (0.7 psi)is typically utilized in this test.

[0078] As test fluid is introduced into the cylinder it typically buildsup on top of the liquid removal system thereby completing an electricalcircuit between the electrodes. This starts the timer. The timer isstopped when the absorbent structure has absorbed the gush of urine, andthe electrical contact between the electrodes is broken. In case, testfluid does not build up in the cylinder, the absorption time is set tobe zero.

[0079] The acquisition rate is defined as the gush volume absorbed (ml)per unit time (s). The acquisition rate is calculated for each gushintroduced into the sample. Of particular interest in view of thecurrent invention are the first and the last of the four gushes.

[0080] This test is primarily designed to evaluate systems having anabsorbent capacity of about 300 ml to 400 ml. If products withsignificantly different capacities should be evaluated, the settings inparticular of the fluid volume per gush should be adjusted appropriatelyto about 20% of the theoretical capacity, and the deviations should berecorded.

[0081] Liquid Retention Test

[0082] The liquid retention test measures the liquid that is retained ina material sample that is temporarily immersed in a test liquid havingdefined surface tension. The test liquids are prepared by usingdistilled water and dissolving a suitable amount of suitable surfactantin the water.

[0083] A sample of the material having dimension of 50 mm length and 50mm width is prepared and weighed. The sample is immersed in the testliquid for about 5 minutes. After taking the sample out of the testliquid, the sample is carefully shaken so that excess liquid can run offfrom the surface of the material sample.

[0084] The liquid retention of the material sample is obtained bymeasuring the wet weight and taking the difference between wet weightand dry weight.

[0085] Collagen Rewet Test Method

[0086] Before executing the test, the collagen film as purchased fromNATURIN GmbH, Weinheim, Germany, is prepared by being cut into circularsheets of 90 mm diameter by using a sample cutter device and byequilibrating the film in the controlled environment of the test room(see above) for at least 12 hours (tweezers are to be used for allhandling of the collagen film).

[0087] At least 5 minutes, but not more than 6 minutes after the lastgush of the above acquisition test is absorbed, the cover plate andweights are removed, and the test sample is carefully placed flat on alab bench.

[0088] 4 sheets of the pre-cut and equilibrated collagen material areweighed with at least one milligram accuracy, and then positionedcentered onto the loading point of the liquid removal system, andcovered by perspex plate of 90 mm diameter, and about 20 mm thickness. Aweight of 15 kg is carefully added (also centered). After 30+/−2 secondsthe weight and perspex plate are carefully removed again, and thecollagen films are reweighed.

[0089] The Skin Hydration Value is the moisture pick up of the collagenfilm, expressed in milligrams.

What is claimed is:
 1. A liquid removal system which comprises aninterface device, said interface device comprising a first zone and asecond zone and having a porous membrane separating said first zone fromsaid second zone, said second zone being adapted to be connected to asuction source, said porous membrane being capable of maintaining asuction in said second zone without permitting air from said first zoneto pass through said membrane into said second zone when said membranehas been wetted with a first liquid; said suction being maintained untilsaid membrane is contacted with a second liquid; and wherein said secondliquid upon entering said first zone and contacting said porous membraneis removed from said first zone by said suction in said second zone bypassing through said membrane into said second zone said first zonehaving a user facing surface, said the second zone having a backsurface, said user facing surface having a urine acquisition zonecharacterized in that said liquid removal system has a skin hydrationvalue of less than 200 milligrams according to the collagen rewet testdefined herein.
 2. A liquid removal system according to claim 1 whereinsaid user facing surface comprises a skin care composition which is atleast partially transferable to the skin of the user during use of saidliquid removal system.
 3. A liquid removal system which comprises aninterface device, said interface device comprising a first zone and asecond zone and having a porous membrane separating said first zone fromsaid second zone, said second zone being adapted to be connected to asuction source, said porous membrane being capable of maintaining asuction in said second zone without permitting air from said first zoneto pass through said membrane into said second zone when said membranehas been wetted with a first liquid; said suction being maintained untilsaid membrane is contacted with a second liquid; and wherein said secondliquid upon entering said first zone and contacting said porous membraneis removed from said first zone by said suction in said second zone bypassing through said membrane into said second zone said first zonehaving a user facing surface, said the second zone having a backsurface, said user facing surface having a urine acquisition zonecharacterized in that said urine acquisition zone is completely coveredby a hydrophobic apertured topsheet.
 4. A liquid removal systemaccording to claim 3 wherein the user facing surface of said hydrophobicapertured nonwoven topsheet comprises a skin care composition which isat least partially transferable to the skin of the user during use ofsaid liquid removal system.
 5. A liquid removal system according toclaim 3 or claim 4 wherein set hydrophobic apertured nonwoven topsheethas a liquid retention of less than 50 mg for a test liquid having asurface tension of about 62mN/m according to the liquid retention rawmaterial test defined herein.